PROJECT SUMMARY Alzheimer?s disease and other related dementias (ADRD) are widely acknowledged as a major cause of morbidity and mortality in older populations. There are racial disparities in prevalence, with older African-Americans being twice as likely as older whites of having ADRD, with more severe symptoms at the time of diagnosis. Treatment intensity of people with ADRD is well documented to differ by race, including differences in health services received such as medication use and end of life care patterns. For example, African-Americans have 1.77 times the risk of having a feeding tube placed at the end of life than white patients. While differences in patient preference across racial and ethnic groups are documented, one major gap in our knowledge is what role physician practice characteristics have on disparities. While disparities could exist because the same physician is treating African-American and white patients differently, an alternative could be that people of different races with ADRD are seen largely by different physicians, with varying experience with either dementia or racial minorities. Furthermore, physicians seeing minority dementia patients may be in completely different physician ?networks,? meaning minorities see physicians who have differential connections to providers with specialized ability to diagnose and treat people with dementia. The influence of physician professional connections on behavior can be studied by drawing on methods developed for the study of social networks. Social networks are structural representations of social interactions and personal or professional relationships. For physicians, social networks consist of colleagues with whom they share information, which can be measured by inferring connections when physicians share patients. The goal of this R03 is to develop preliminary data and methods to study the influence of social networks of physicians on disparities in end of life (EOL) care delivered to white and African-American Medicare beneficiaries with ADRD. We propose to address these questions developing social networks of physicians who provide EOL care to dementia patients, stratified by race, and study how these networks are associated with the quality and racial disparities of that care. Thus, this R03 is designed to: (1) construct and summarize physician patient-sharing networks for dementia patients and describe the relationship between network characteristics of their predominant provider of care and end of life outcomes; and (2) elucidate the relationship between physician patient-sharing networks and the disparities by race in intensity and quality of care received at the end of life for dementia patients. With greater understanding of the relationship between disparities in quality of care and physician networks, this R03 will form the basis for future research at Dartmouth to inform new areas of health economic and services research, and potentially many other questions regarding physician influence of healthcare quality and use for people with Alzheimer?s disease.